{"id":25724,"date":"2019-06-19T15:27:04","date_gmt":"2019-06-19T19:27:04","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=25724"},"modified":"2019-06-20T13:40:10","modified_gmt":"2019-06-20T17:40:10","slug":"backing-up-vm-image-files-to-internet-backup-services","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2019\/06\/19\/backing-up-vm-image-files-to-internet-backup-services\/","title":{"rendered":"Backing Up VM Image Files to Internet Backup Services"},"content":{"rendered":"

Adam Engst<\/a>:<\/p>\n

\n

Seriously? Code42 is actually admitting that CrashPlan may not back up large files correctly? Isn’t that Job #1 for any backup app?<\/p>\n

[…]<\/p>\n

After the initial upload, apps like Backblaze and CrashPlan do block-level data deduplication, which means that they analyze small blocks of each file, compare them to what’s already backed up, and copy only those blocks that are new or changed. It might seem as though large files wouldn’t present a problem after initial backup as long as they didn’t change all that much. However, as Yev pointed out, the resources necessary to analyze all the blocks in a multi-gigabyte file are significant—you need enough drive space to store a copy of the file, and then the backup app has to spend a lot more time and CPU power analyzing all those blocks.<\/p>\n

[…]<\/p>\n

For these reasons, Backblaze also excludes VM image files and other large file types (it also doesn’t back up system files or applications), as you can see in the app’s Exclusions screen.<\/p>\n<\/blockquote>\n

In both cases, you can adjust the exclusion lists to include these files.<\/p>\n\n

Previously:<\/p>\n